1. Field of the Invention
The present invention relates to a pop-up flash of a camera which pops up out of a camera body in flash photography.
2. Description of the Related Art
Various types of cameras are equipped with a pop-up flash whose light emitting portion is movable between a retracted position, in which the light emitting portion is retracted into a camera body, and a fully-lifted position, in which the light emitting portion projects from the camera body. It is generally the case that the light emitting portion of the pop-up flash is continuously biased toward the fully-lifted position (i.e., in a projecting direction) and that the light emitting portion is held in its retracted position against the biasing force by a locking mechanism. The biasing device which continuously biases the light emitting portion toward the fully-lifted position is made of a spring so that the resiliency of the spring (the torque produced by the spring) becomes maximum when the pop-up flash is held in the retracted position and gradually reduces as the light emitting portion approaches the fully-lifted position. Accordingly, the speed of movement of the light emitting portion gradually reduces in a direction toward the fully-lifted position from the retracted position as approaching the fully-lifted position.
In the pop-up flash, the light emitting portion needs to be securely moved to the fully-lifted position, and accordingly, it is required to keep the movement speed of the light emitting portion above a certain movement speed even when the light emitting portion comes near the fully-lifted position. However, the movement speed of the light emitting portion gradually reduces in a direction toward the fully-lifted position from the retracted position as approaching the fully-lifted position as described above. Conversely, the movement speed of the light emitting portion does not need to be so fast from the retracted position to an intermediate position in the projecting direction so long as the light emitting portion can be securely moved in an initial moving stage thereof from the retracted position toward the fully-lifted position.